1. Technical Field
The present invention relates to a package containing a plurality of cylindrical articles such as batteries, and a method of fabricating the same.
2. Background Art
Heretofore, various packages for cylindrical articles have been devised and commercialized. In particular, perforations, slits, or the like are formed in wrap films to facilitate removal of the cylindrical articles and to identify that the wrapped cylindrical articles are unused (virginity).
For example, a conventional package is fabricated by wrapping a plurality of articles in a heat-shrinkable film, and heat-shrinking the heat-shrinkable film. In this kind of package, for easy removal of an article to be wrapped, a perforation (opening means) that breaks under force is formed in the portion of the heat-shrunk film that is located in the space between the film and the wrapped articles.
In the conventional method for fabricating such a package, there are two main methods: one is to form a perforation in the heat-shrinkable film before wrapping the film around the cylindrical articles, and the other is to form a perforation in the film after the film has been wrapped and heat-shrunk around the articles. In the former case, it is relatively difficult to position the perforation with respect to the cylindrical articles after wrapping and heat-shrinking. A further problem is that the perforation may be deformed by heating, resulting in decreased package strength or variations in strength from package to package. On the other hand, the latter method has involved the problem that the cylindrical articles may be scratched.
For example, Japanese Unexamined Patent Publication No. Hei 8-122981 discloses a package in which a plurality of cylindrical articles (magazines containing photographic sensitive materials), each packaged in a cylindrical moisture-proof case, are wrapped together by heat-shrinking a heat-shrinkable film around the articles integrally with the moisture-proof case.
Further, Japanese Unexamined Utility Model Publication No. Hei 6-37175 discloses a package which is fabricated by wrapping a plurality of articles to be wrapped in a heat-shrinkable film, and heat-shrinking the heat-shrinkable film. In this package, for easy removal of an article to be wrapped, a perforation (unwrapping means) that breaks under force is formed in the portion of the heat-shrunk film that is located in the space between the film and the wrapped articles.
However, in these packages, since the entire set of cylindrical articles is wrapped in a heat-shrunk film, the cylindrical articles cannot be taken out individually without removing the entire heat-shrunk film. As a result, it is not possible to take out an article individually and yet leave the remaining articles wrapped to retain their unused state (the so-called virginity).
Such a package capable of securing the virginity of each individual cylindrical article is disclosed, for example, in Japanese Unexamined Utility Model Publication No. Sho 52-64680. This package uses a heat-shrinkable film tube of a synthesized resin. The film tube is formed with a slit and/or perforation, and a separating means are formed, spaced apart from one another by a distance equal to the width of each dry battery. According to this publication, after forming the slit, perforation, and separating means, dry batteries are inserted in the film tube in parallel, and then the film tube is heat-shrunk to complete the fabrication of the package.
However, since a heat-shrinkable film tube, in general, is thin and lacks rigidity, if it is attempted to insert dry batteries into the heat-shrinkable film tube with slits, etc. formed in advance, the film may lose its shape and the dry batteries cannot be inserted neatly. Even if the dry batteries could be inserted, wrinkles or folds may be produced in the film tube, impairing the aesthetic appearance of the package. Furthermore, since the slit portions of the film are in the so-called idle state, when broken to separate each individual article, the perforated portions of the film become loose and the film is unable to fix and retain the wrapped cylindrical articles in a reliable manner.
That is, with the method of the above publications, it has not been possible to reliably obtain a package capable of ensuring the virginity of each individual cylindrical article.
Also in these days, it is desired to increase the number of batteries that can be packed in such a package, but if many batteries are packed in one package, all the batteries will come out separated upon opening the package, which inconveniences the consumer.
To address this problem, it has been practiced to employ a packing method generally known as the double shrink packing method in which a plurality of unit packages, each containing a plurality of batteries, are arranged and wrapped together in a second heat-shrinkable film (outer film). In one example, such a composite package is fabricated by arranging three unit packages in parallel, each containing four batteries, and wrapping them together in a second heat-shrinkable film.
However, since the total weight of the plurality of unit packages is considerably high, high strength is required for the second heat-shrinkable film to fix and retain them. This gives rise to the problem that the package is difficult to be opened because a relatively strong force is needed to open the package containing the plurality of unit packages.
In view of the above-outlined problems, it is an object of the present invention to provide a package for a plurality of cylindrical articles, capable of removing each cylindrical article individually and retaining the virginity of each remaining article even when the cylindrical articles are removed one by one.
It is another object of the present invention to provide a package for cylindrical articles and a method of fabricating the same, in which a slit can be easily formed in a boundary portion between adjacent cylindrical articles as well as in the upper end and lower end faces of the package without scratching or nicking the cylindrical articles.
It is a further object of the present invention to provide a package (double shrink package) fabricated using the above so-called double shrink packing method, in which the package permits each individual unit package to be removed by easily breaking the outer film while reliably and stably maintaining the fixed and retained state of the unit package.